Safety apparatus for rotary press

Abstract

A safety apparatus for a rotary press comprises a detector disposed on a side of a plurality of printing units in order to detect entry of a foreign object between the printing units, the detector consisting of light projecting units and light receiving units; a push button provided on the printing unit and pushed after completion of checking performed before initiation of automatic plate-replacing operation of the printing units; and a controller for starting the automatic plate-replacing operation and detecting operation of the detector when a predetermined time elapses after operation of the button.

What is claimed is:  
     
       1. A safety apparatus for a rotary press having a plurality of printing units, comprising: 
       a detector disposed on a side of said rotary press to cover a zone including each of said plurality of printing units and adapted to detect entry of a foreign object into said zone;  
       a switch provided on each printing unit of said printing press; and  
       control means for starting operation of said printing units and detecting operation of said detector when a predetermined time elapses after all of said switches are operated sequentially.  
     
     
       2. A safety apparatus for a rotary printing press according to  claim 1 , wherein said detector includes a light projecting unit and a light receiving unit; and self diagnosis of said light projecting unit and said light receiving unit is performed when a second predetermined time elapses after all of said switches are operated. 
     
     
       3. A safety apparatus for a rotary press according to  claim 1 , wherein the operation of said printing units is a plate replacing operation for removing an old plate from a plate cylinder of each of said printing units and for attaching a new plate to the plate cylinder. 
     
     
       4. A safety apparatus for a rotary press according to  claim 1 , wherein said control means stops the operation of the printing units when said detector detects a foreign object. 
     
     
       5. A safety apparatus for a printing press according to  claim 1 , wherein the operation of said printing units is begun after said detecting operation is commenced. 
     
     
       6. A safety apparatus for a rotary printing press having a plurality of printing units, comprising: 
       a detector disposed on a side of said rotary press to cover a zone including each of said plurality of printing units and adapted to detect entry of a foreign object into said zone, said detector including a light projecting unit and a light receiving unit;  
       a switch provided on each printing unit of said printing press; and  
       control means for starting operation of said printing units and detecting operation of said detector when a predetermined time elapses after all of said switches are operated sequentially;  
       a first self diagnosis of said light projecting unit and said light receiving unit being performed when a second predetermined time elapses after all of said switches are operated, and a second self diagnosis of said light projecting unit and said light receiving unit is performed after the completion of the operation of said printing units.  
     
     
       7. A safety apparatus for a rotary press having a plurality of printing units, comprising: 
       a detector disposed on a side of said rotary press to cover a zone including each of said plurality of printing units and adapted to detect entry of a foreign object into said zone, said detector including a light projecting unit and a light receiving unit;  
       a switch provided on each printing unit of said printing press; and  
       control means for starting operation of said printing units and detecting operation of said detector when a predetermined time elapses after all of said switches are operated sequentially, said control means measuring time between operation of the first switch and operation of the last switch, and when the time is in excess of a preset time, all of the switches are reset.